Allegations of cheating by students in immigration exams has seen the launch of a corruption investigation.

Australia’s largest international student service, IDP Australia, is investigating possible corruption among its staff after students in Sydney were caught cheating on exams it conducts for the Department of Immigration, The Sun-Herald newspaper reports.

Copies of the May International English Language Testings System (IELTS) exam were sold for between $12,000 and $18,000, one source claims.

“These have been leaking out for months,” the source told newspaper.

“It’s like a chain of command. It came from the official service who gives it out and takes his cut.

IDP would not confirm how many people had been caught cheating.

“Cheating in IELTS tests is not commonplace,” an IDP Australia spokeswoman said.

“‘However given the high stakes involved, attempts to cheat or engage in other fraudulent activity such as identity fraud do occur.

“Recently in Australia a number of test takers have been detected in their attempt to cheat in the IELTS test. Whether or not it was an internal problem, we don’t know.”

IDP is investigating the matter.

Meanwhile, the Immigration Department has defended its outsourcing of English tests, which have been handled by IDP since 1994.